• Support PF! Buy your school textbooks, materials and every day products Here!

A beam of red light has twice the intensity as a second bean of the same color

  • Thread starter looi76
  • Start date
  • #1
81
0

Homework Statement


A beam of red light has twice the intensity as a second bean of the same color. Calculate the ratio of the amplitude of wave.

Homework Equations


[tex]intensity \propto (amplitude)^2[/tex]

The Attempt at a Solution


[tex]1^{st} \mbox{ beam} = 2I[/tex]
[tex]2^{nd} \mbox{ beam} = I[/tex]

I don't know if this step is correct and I don't know what to do next?!
 

Answers and Replies

  • #2
303
0

Homework Equations


[tex]intensity \propto (amplitude)^2[/tex]

The Attempt at a Solution


[tex]1^{st} \mbox{ beam} = 2I[/tex]
[tex]2^{nd} \mbox{ beam} = I[/tex]
[tex]I_1=2 I_2[/tex]

[tex]\frac{I_1}{I_2}=2[/tex]

What can you do to the above relation (given your relevant equation) to convert it to a ratio of amplitudes?

Regards,

Bill
 
  • #3
81
0
[tex]intensity \propto (amplitude)^2[/tex]

So, it will be [tex]1:4[/tex] ?
 
  • #4
Defennder
Homework Helper
2,591
5
No, start off by expressing both intensities I = kA^2. Then compare the ratio of each amplitude to the other.
 
  • #5
303
0
[tex]intensity \propto (amplitude)^2[/tex]

So, it will be [tex]1:4[/tex] ?
No. Try what Defennder suggested to see why.

Regards,

Bill
 

Related Threads for: A beam of red light has twice the intensity as a second bean of the same color

Replies
2
Views
3K
Replies
2
Views
2K
Replies
4
Views
23K
Replies
1
Views
1K
  • Last Post
Replies
1
Views
10K
Replies
5
Views
594
Top